Hello,

Been lurking around here for a while as I get ready to buy my first Dodge (but third diesel). Have a guy at work that is letting one go cheap. 2003 2500 SLT 4x4 CC 6 speed with the Edge and 4.10 rear end. I will give him my 97 yukon with 120k plus $15,000. His truck has about 80k on it. Anyway, my question is...can I get a 6th gear swap for this truck to get the benefit of the lower gears in 1-5 and nice highway gear as well? You can do this on my 03 TDI Jetta so I thought it might be possible to do it on the Dodge.

Any help would be appreciated.

Thanks,
Will

 

No can't be done. Its not a 40lb Jetta tranny your dealing with. Its a 360lb NV5600 that takes a 20 ton press to work on (and there is no other gears but OEM).

You can do a differential gear swap to 3:73 which will help out. 4:10's are useless unless you are towing heavy in my opinion or you are running super big tires like 37's.

Any other questions?

PS My wife has a Jetta 1.8T that thing will scoot!

 

I appreciate the response. Yes, the Jetta does scoot. Especially with the new bigger tips for the injectors. Better mileage and tons more power.

Is the 3.73 the only option at this point? I would like to be at 1800-2000 rpms at 75mph. From the history of the truck I know it already gets 20mpg but the guy hardly ever takes it over 60mph. I intend to use it on the highway a good bit and would like it be economical. I also would like to pull a travel trailer now and then. What is my best option on the 6 speed. Should I go 12 speed with a Gear Vendors unit?

 

What is a Gear Vendors unit? I have an auto with 4.10's and am interested in getting lower rpms on the highway now im only pulling around 17-18mpg at 65 mph btw auto is only 4 spd

 

Gear Vendors is a gear splitter with a higher overdrive or you can get one with a lower 1st gear (I think). I definately don't need a lower first gear in the truck I am buying. Typically you would take off in third gear for normal driving. May use 1 and 2 for heavy loads. You can find Gear Vendors online very easily using a search engine.

Will

 

great ill look thanks

 

Gear splitters are well over 3k.From what I've read a increase of 1 to 1.5 mpg.Buy a lot of fuel for 3k plus.

 

If I remember correctly the Gear Vendors only does overdrive and will not operate in 1st. The unit from U.S. Gears can get with over or under drive that will operate in any gear.

 

Not sure about the new ones, but I had one on an old Ford F250/6.9 with a C6 tranny and the GearVendors unit would work in all forward gears (tho not much use for 1st OD). They are pretty well built and trouble free in my experience, but yes, you can buy a lot of fuel for $3K if economy is your goal.

I think they are rated for 30K# GVWR as used in RV/motorhomes.

 

Change the rear end gears to 3.73. Or why cant one look for a older complete rear end ,housing and all, from a wreck that has 3.55 gears?? Would it fit???

 

The gear vendors unit requires a speed of 25mph before it can be turned on or the unit will burn up. At speeds of less that 25 the unit cant build enough hydraulic pressure to keep the internal clutch engaged and the unit slips this clutch and developes immediate heat and fries itself. they also cant be used in 6th gear while towing because the overdrive ratio is to tall and the truck becomes inefficient and also adds to much load to the already small 6th gear in your tranny. it doesnt break the gear but over heats it which makes a lock nut fall off of the gear and this nut then falls into a gear cluster and the rest you can imagine. the gear vendor is a 36% overdrive which will drop you 6 to 700 rpms in 6th gear which is way to much for towing . this is why gear vendor recomends you tow in 5th over which is the same exact ratio as the 6th gear you have now. kinda dumb huh? would be great for bobtail highway driving at 75mph or more though. thats why I am currently installing a mitchell overdrive which is only a 350 to 400 rpm drop or 18% overdrive ratio. its also a manual shift full synchro unit , not electronically controlled like the GV unit and not a complicated to operated gear crunching unit like the US gear. mine is also 35000 pound rated! its a shame you cant buy them anymore huh? I found mine used and Just had the unit totally rebuilt by mitchell who is still in bussiness and stock all the parts for them except the cases and am about to put it in. I will have 12 manually shifted forward speeds and 2 reverses and if you count the transfer case, 18 forward speeds and 3 reverses . my 6 speed dually with 373 gears will now have a 100 rpm higher final drive ratio than it would with an automatic.

 

Um, isn't that the 5th gear nut on the NV4500 (5 speed) that had that problem. Have never heard of a 6 speed with this problem.

As for the final ratio problem, either get the 3.73 ring and pinion or find a donor truck that has been wrecked.

 

x2-- word for word.

 

3.54's/4.10's from 2nd gens were Dana

3.73's/4.10's on 3rd gens are American Axle Manufacturing.

Not interchangeable.

although the grapevine is active with thoughts of bringing it back to make up for lost fuel economy on the new emissions engines.

 

Got the truck today and really like it. Much better storage gizmos than my 01 F250 had. Plenty of power with the Edge EZ. Probably won't add any other box since I went through the pain of completely grenading my powerstroke.

Probably would like to do a gear swap in the next 6 months or so. Seems like if I keep the truck and diesel prices keep going up it would make sense to do the swap. Should be easy enough to find a guy that wants to swap. Then maybe I would only be paying labor.

What would my rpm's drop to at 70, 75 and 80 mph in 6th gear if I did the swap??

Here is what GV sent me via email: Here are the numbers you are looking for.

Factory sixth gear(.73) Double overdrive(.57)
3.00 final drive 2.38 final drive
70 mph 2352 1865
75 mph 2521 1975
80 mph 2688 2132

The mathematical equation is (336 x MPH x FDR) / Tire Diameter

Remember the final drive ratio must be found by multiplying the factory transmission gear ratio by our .78 overdrive, and then multiply that by the rear gear ratio. Your example would be factory sixth gear times .78 (.73 x .78 = .57). So, the above numbers would give you a 3.00 effective final drive in just factory sixth gear, and a 2.38 effective final drive in double overdrive.

Would really be nice to have 3.73 and GV unit (just for fun).

Thanks for your replies.

Will